Whipstock



Jan. 11, 1944. c, 1 WALKER WHIPSTOCK Filed Sept. 10, 1941 lllllllllllllllllll l ll, xlllllllllllllllllllll,

Munnik-Imm? lill" x lclutch construction and Patented Jan. 11, 1944 UNITED STATES PATENT OFFICE 2,338,788 wHIrs'rocK clinton L. Walker, Piedmont, Calif. p Application September 10, 1941, Serial No. 410,259

Claims.

My invention relates to oil well drilling apparatus and particularly to a whipstock employed in the casing for producing deflection drilling.

In my Patent No. 2,132,061, issued October 4, 1938, I have illustrated a whipstock for producing deflection drilling over which the present whipstock is an improvement. 'Ihe whipstock of the prior patent depended upon a pair of cables for lowering and raising the whipstock from the casing. Some objection was raised to the use of the cables for lowering and raising the whipstock because the cables tangled and failed to accurately orient the sloping surface of the whipstock relative to the direction in which the deflection drilling was to occur.

The whipstock embodied a block of metal having a sloping cam face and a conical mandrel which operated cna plurality of clutch plates for moving the clutch plates radially into engagement with the inner surface of the casing to lock the whipstock in position. The whipstock could be secured to the inner side of the casing at any point at which the deflection drilling was to occur. After the whipstock is set in position, av milling tool, mounted on the end of the drill stem, cut through the casing and drilling was continued through the opening in the casing in the usual IThe present invention pertains to an improved A. operating device there` for, which embodies a stem by which the whipstock is lowered in the casing and accurately oriented to have the cam surface face the direction in which the deecton drilling is to occur. stem is thereafter released from the cam block, but continues to support a spindle which extends through the block and mandrel to support the clutch plates. The cam block drops and the mandrel forces the cam plates radially into the metal of the casing. A positive lock is thereby provided which prevents the whipstock from moving downwardly in the casing as the milling tool cuts through the casing wall.

After the completion of the drilling operation, the whipstock may be removed from the casing by the use of a stem which is guided into the central threaded opening of the camblock and screwed in position. When the stem is raised, the cam block, along with the conical mandrel, moves v upwardly therewith, thereby releasing the clutchA plates from the wall of the casing, permitting the whipstock to be drawn upwardly by the stern sections out of the top of the casing.

Accordingly, the main objects of my invention are: to provide a whipstock with a central threaded opening engageable by the end of a stem `by which the whipstock is lowered and raised within the casing; to provide a series of clutch-plates on the bottom of the whipstock which are attached to a plate on the end of the stem which The, v

block without releasing the spindle `trated in Fig. 2, taken on the trated in Fig. 2, taken on. th

is supported thereby after the cam block is released therefrom; to provide a positive support for a. series of radially movable cam plates which are moved outwardly by a tapered mandrel 'on vthe end of a cam block, which is released from a supporting element to move the cam plates outwardly as they are supported against further movement downwardly in the casing; to provide' a thread on the end of the spindle supporting the plurality of clutch plates which is of ner pitch than the exterior threads on the supporting stem to permit the stem to be released from the cam therefrom; to

provide a drag spring on the end of the whipstock yof a strength suilicient to approximately support the whipstock within the casing; to provide a whipstock with a lowering device which accurate- 1y orients the whipstock and maintains the cam block spaced from te clutch plate and which releases the cani block but supports the clutch plates when positioning the whipstock Within a casing; :o providea whipstock which may be removed from the carrier by a supporting stem which engages the cam block portion for raising ther portion and releasing the clutch plates from lengagement with the casing wall; and in general Vto provide a whipstock for the casing of a Well Awhich is accurately oriented and attached to the lwall of the casing and which may be removed therefrom. i

Other objects and features of novelty of my invention will be specifically pointed out or will become apparent upon referring, for a better understanding of my invention, to the foliowing de- "sc'ription-Y taken in conjunction with the accompanying drawing, wherein: v

Figure 1 is a sectional View of a well casing and a whipstock being lowered therein embody- Aing features of my invention;

Fig. 2 is a view in elevation of illustrated in Fig. 1;

Fig. 3 is a sectional view of the whipstocl:`

the structure' illusline 3-3 thereof; f of the structure illuse line 4-i thereof;

of the structure illustaken on the line -5 thereof;

Fig. 4 is a sectional view Fig. 5 is a sectional View trated in Fig. 2, and

Fig. 6 is a view of structure, similar to that i1- lustrated in Fig. 1, with the whipstock being raised from the casing after the well drilling operation.

In Fig. 1, I have illustrated a well casing I!) at a point from which deflection drilling is to take place. 'I'his may be necessary 'because of the loss vof a string of tools, from a desire to deflect the bore from the original bore or for other reasons.

l The Whipstock embodying my invention comprises'a camblock Il having a sloping cam face I2 and a conical mandrel I3 on its lower end. A

' conical surface central opening I4 is provided through the mandrel having a thread I5 which is engaged by a thread I6 on the outer surface of a supporting stem I'I. Below the thread, the aperture I4 is reduced in diameter at I8 through which a spindle I9 projects having a thread 2| on its end which is of finer pitch than the thread I5. The thread 2l engages a similar thread 22 on the inner Wall of the stem I'I.

A key 23 is provided on the spindle I9 which prevents the spindle from rotating While permitting it to move a slight amount longitudinally of its length. The end of the spindle I9 contains a square end portion 24 on which a plate 25 is mounted supporting a plurality of studs 25 in slots 21. Each of the studs 2G is attached to a clutch plate 23 having an inner slotted tapered surface 29 which mates with the tapered of the mandrel I3. The mandrel with projecting lands 3l which enthe surface 29 `of the clutch is provided gage the slots in plates 28. A drag spring 32 is supported on the square end portion 24 against the plate 25 by a nut 26.

The whipstock is supported on a plurality of stem sections Il which are attached to each other as the whipstock is lowered into the casing I0. The whipstock is oriented, that is to say, is positioned to have the sloping cam face I2 disposed in the direction in which the deflection drilling is to occur. Care is exercized as the additional sections of the stems I'I are attached and lowered to prevent the whipstock from changing its position so as to retain it oriented at all times.

After suflicient sections of the stem I'i have been added and lowered into the casing, the whipstock is positioned at a point where the de- Flection drilling is to occur. The drag 32 exerts sufficient pressure on the casing wall to permit the stem I'i to be screwed from the thread I5 without changing the position of the cam block I l. When the cam block I I is released, the stem I1 continues to support the spindle I9 to which the clutch plates 28 are attached. The cam block II drops and the plates 23 are moved radially by the conical mandrel I3. A plurality of sharp longitudinal surfaces 33 on the outer faces of the clutch plates 23 are forced into the inner wall of the casing I0. This rmly clamps the whipstock in position Within the casing, after which the stem I'I is released from the thread 2l on the end of the spindle I9 and is removed from the casing. A suitable cutter is then employed on the end of the drill stem for cutting through the Wall of the casing, through which the deflection drilling occurs.

After the drilling operation has been completed, the whipstock may be removed by the stem I1, the endmost element 34 of which may be provided with a guide plate 35 having a thread IB near the end from which a conical end portion 36 protrudes. The plate 35 and end 36 accurately guide the end of the element 34 into the aperture I4 in the cam block II. After the thread I5 has engaged the thread i3 of the cam block, the cam block is raised along with the conical mandrel i3 which moves from engagement with the cam plates 23 which are free to shift radially inwardly out of contact with the inner wall oi the casing III.

After the cam plates are released, the Whipstock may be drawn upwardly out of the casing. The use of the square end portion 24 of the spindle I9 prevents the drag spring 32 from turning, thereby maintaining the Whipstock II oriented at all times. The drag spring 32 also prevents the whipstock from turning when the stem II is unscrewed from the thread I5 of the cam plate II. A slight longitudinal movement of the spindle IS permits the turning of the stem I'I in the thread I5 while turning on the finer thread 2I of the spindle. The use of the splines 3| maintains the shoes 23 oriented relative to the mandrel I3 and all elements of the whipstock are maintained in operating relation to each other.

I claim as my invention:

l. A whipstock including in combination, a cam block having a clutch expanding mandrel, a spindle extending through said Gam blocls and mandrei, a plurality of clutch plates supported for radial movement by said spindle, and a stern having threaded engagement with the cam block and spindle, the threads being such as to permit the disengagement of the stem from the cam block while maintaining the spindle secured thereto.

2.. A whipstock including in combination, a cam block having a clutch expanding mandrel, a spindle extending through said cam block and mandrel, a plurality of clutch plates supported for radial Amovement by said spindle, a stem having threaded engagement with the cam block and spindle, the threads being such as to permit the disengagement of the stem from'the cam block while maintaining the spindle secured thereto, a drag spring on the lower end of the spindle, and means for retaining said drag spring from turning relative to said spindle.

3. The combination in a whipstock, or' a cam block having a sloping cam surface, a clutch expanding mandrel on the lower end of said cam block, a spindle extending through said mandrel and cam block and retained against rotation relative thereto, a plate supported by said spindle, a plurality of cam plates supported by said spindle plate for radial movement, means for maintaining said cam plates and mandrel against relative rotation, and a drag spring mounted on the end of said spindle.

Ll. The combination in a whipstoclf., of a cam block having a sloping cam surface, a clutch expanding mandrel on the lower end of said cam block, a spindle extending through said man drel and cam block and retained against rotation relative thereto, a plate supported by said spindle, a plurality of cam plates supported by said spindle plate for radialv movement, means for maintaining said cam plates and mandrel against relative rotation, a drag spring mounted on the end of said spindle, and a stem independently secured to the cam block and spindle in such manner as to be releasable from the former without being separated from the latter.

5. The combination in a whipstcck, of a cam block having a sloping cam surface, a clutch eirpanding mandrel on the lower end of said cam block, a spindle extending through said mandrel and cam block and retained against rotation rela tive thereto, a plate supported by said spindle, a plurality of cam plates supported by said spindle plate for radial movement, means for mailitaining said cam plates and mandrel against relative rotation, a drag spring mounted on the end of said spindle, and a stern for engaging the cam block and collapsing the cam plates when raising the whipstock.

CLINTON L. WALKER. 

